Always good advice, although the amount of savings is slightly wrong. UPC (Unified Plumbers Code) regulates bathroom faucets at a flowrate of about 2.5 gal/min so you save about 5 gal.

To build on this theme, fill up your water glass for brushing your teeth using the water you get out of your shower when your preheating the shower. Also, add a Ladybug adapter to your showerhead. It lets your shower preheat without wasting extra water.

WOW! Flow rate of water is very important.....
Although, we will all have to be able to consume and retain much more water than is currently possible to prevent water from destroying us..
KEEP SAVING MONEY!!!!!

Brushing your teeth isn't the only time people tend to waste water in the bathroom. Washing your hands is another one of those times where you can get your hands wet, shut off the water, soap up, then turn the water back on for a quick rinse. And for those that are really serious about saving water (like I am), when taking a shower, you can follow the same process as washing your hands. The average single family home uses about 13.2 gallons of water per day just for showers, so taking a dryer shower can save a lot of water.

Actually, according to statistics the average length of a shower is 8 minutes and the standard flow rate for a shower head is 2.5 gal/min (1.6 for low flow units like a Roadrunner) so that's 20 gallons per shower, not counting the cold stuff going down the drain while your shower heats up.

True. The average I gave was a national statistic that is much lower, I'm sure, because not everyone takes a shower every day. I've been planning to stop-up the tub one time when I take one of my "dryer showers", just to see how much water that uses. I'll let you know what I find out.

I just got in my first shipment of Roadrunner low flow shower heads and I've got to say I'm impressed with the power coming out. It's hard to believe it's saving nearly a gal/min. I wasn't going to use one because I had thought my daughters were using the removable shower head for getting through their hair, but found out that they weren't and considering that they take long showers I thought it was worth the money.

What I did was put a stopper in the drain, took my shower, then scooped/sponged out the water. It came to a total of just under 2 gallons!

Based on your statistic of a 20 gallon average, that means my shower used 90% less water. If everyone in the U.S. showered this way, we could save as much as 5 billion gallons of water per day. At that doesn't even cover the cost of energy to heat the water.

Shaving

I use an ordinary razor for shaving and it is also impotant of course to turn the water on and off when doing it. But here's a question: Do you think that shaving with a good electric shaver is environmentally more friendly than shaving with a razor? I imagine that electricity usad by the shaver is (at least potentially) less eco-damage than using much water for shaving. It depends of course on how much water one uses for shaving and on the efficiency of the electric shaver.